Vulcanisation of 2-chlorobutadiene-(1, 3) polymers



United States Patent VULCANISATION OF 2-CHLOROBUTADIENE-(1,3) POLYMERS Helmut Freytag, Koln-Stammheim, Friedrich Loher,

Leverkusen-Bayerwerk, and Richard Wegler and Julius Peter, Leverkusen, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application June 30, 1955, Serial No. 519,233 Claims priority, application Germany July 6, 1954 6 Claims. (Cl. 260-923) do not always .produce satisfactory results, and in particu-.

lar the mechanical values of the resulting vulcanisates usually do not 'conform to practical requirements.

Organic compounds which are added as accelerators to polymers or copolymers of 2-chlorobutadiene-(1,3), examples of such compounds being hexamethylene tetramine, butyraldehyde amine accelerators, pyrocatechol and its derivatives, such as the di-o-tolyl guanidine salt of pyrocatechol boric acid, and also 4,4'-diaminodiphenyl methane, frequently show a pronounced tendency to cause the vulcanisation to begin prematurely. Other disadvantages are that the mechanical properties of the vulcanisate obtained are inadequate.

Cyclic thioureas and their N.N'-dimethyl substitution products, more especially ethylene thiourea (Z-mercaptoimidazoline) and corresponding derivatives with a greater number ofcarbon elements have also been proposed and used as accelerators for polymers and copolymers of 2- chlorobutadiene-(1,3), and in this respect reference is made to United States Patent No. 2,544,746. However, these compounds are comparatively expensive to manufacture.

It is an object of the present invention to provide a new class of vulcanisation accelerators.

It is another object to provide effective accelerators for the vulcanisation of 2-chlorobutadiene-( 1,3) polymers.

It is still another object to provide effective accelerators for the vulcanisation of 2-chlorobutadiene-(1,3) polymers and copolymers thereof with vinyl or diene compounds.

Further objects will become apparent from the following description.

It has now been found that compounds which are effective accelerators for polymers and copolymers of Z-chloro butadiene-(l,3) and which can be prepared in a simple manner are hexahydrotriazine compounds which have the general Formulae I and II:

R1 R: as.

I Ra Ra d where R represents a hydrogen atom, saturated or unsaturated straight-chain or branched alkyl radical with l-6 carbon atoms, a hydroxyalkyl or aminoalkyl radical, ora corresponding radical, the carbon chains of which are broken by the hetero-atoms oxygen, nitrogen or sulphur, or an aralkyl, cycloalkyl or heterocyclic radical; R, is the same as R and represents a hydrogen atom, an

allryl radical with 1-6 carbon atoms or an aryl radical.

or cycloalkyl radical; R is the same as or different from R and represents a hydrogen atom, an alkyl radical with 1-6 carbon atoms or an aryl, cycloalkyl or aralkyl radical;

R represents an alkylene radical with 1-6 carbon atoms,

which can be broken by hetero-atoms, such as oxygen, sulphur or nitrogen, or it can represent a direct NN bond. These compounds are also characterised by, the fact that they have no dis'colouring properties and are odourless, and also by a high degree of safety in' working up. They also impart very good mechanical properties to the vulcanisates.

Compounds of the above type are described by Pacquin (Ang.Ch. (A) 60 (1948) 267-271) and, following the instructions set out therein, these compounds can easily be obtained by the condensation of one mol-of thiourea or a monoor disubstitution, product thereof (for example a diphenyl-, phenyl-, cyclohexyl-, dicyclohexyl-, methyl-, dimethyl-, dibutyl-, or benzyl-thiourea) with 2 1 mols of an aldehyde, more especially formaldehydeor acetaldehyde, or even benzaldehyde or hexahydrobenzaldehyde, and 1 mol of a primary amine (methyl-, ethyl-, propyl-, isopropyl-, butyl-, isobutyl-, allyl-, benzyl-, hexahydrobenzyl-, or furfuryl-amine or ammonia). The bis- 1 compounds of the type shown in Formula II are correspondingly prepared by the reaction of an aldehyde and a thiourea with a diamine or hydrazine.

Accordingly, the present invention provides a process for the vulcanisation of polymers of 2-chlorobutadiene- '(1,3), or copolymers thereof with vinyl or diene compounds, wherein a condensation product of a thiourea, an aliphatic or aromatic aldehyde, and a primary monoamine or diamine, ammonia or hydrazine, is used as a vulcanisation accelerator. The possibilities of variation in the preparation of the triazine compounds are practically unlimited.

' The condensation products of typeI are soluble in organic solvents such as methanol and dioxane. Owing to the fact that they are generally water-soluble, they can with advantage be introduced into latices of 2-chlorobutadiene-( 1,3 polymers.

For the production of vulcanisable mixtures, the products I and II can be incorporated as such into the polymers, or if desired can be incorporated in admixture with suitable plasticisers, such as those usually employed for the working up of these polymers, or with fillers. The accelerators used in the process of the present invention are used in amounts of about 0.2-5 preferably 0.52%,

calculated on the polymer. They are suitable for use in mixtures containing carbon black and also for usein mixtures with light fillers.

Some of these perhydrotriazine compounds which are suitable for use as accelerators are mentioned below by way of example:

r; a 2-thio-5-isobutyl perhydrotriazine-( 1,3,5), M. P. 140-142 Z-thio-S-cyclohexyl perhydrotriazine-(1,3,5), M. P. 176

Z-thio-S-hydroxyethyl perhydrotriazine-(1,3,5), M. P.

2-thio-3,5-dirnethyl perhydrotriazine-.(1,3,5), M. P. 141- 2-thio-1-phenyl-5-methyl perhydrotriazine-(1,3,5), M. P.

l68-169 C. (with decomposition) 2-thio-5-hexahydrobenzyl perhydrotriazine-(1,3,5), M. P.

2-thio-4,5,6,-trimethyl perhydrotriazine-(1,3,5), M. P.

164-166 C. (with decomposition) 2-thio 5-benzyl perhydrotriazine-(1,3,5), M. P.

2-thio-1,3-diphenyl 5 methyl perhydrotriazine-(1,3,5),

M. P. ISO-182 C.

2-thio-4,6-dimethyl perhydrotriazine-(1,3,5), M. P. 180

C. (with decomposition) Sym. ethylene-bis-(2-thio-perhydrotriazine-(1,3,5), M. P.

209-210 C. (with decomposition) Sym. hexamethylene bis (2 thio perhydrotriazine- (13.5)), M. P. ISO-181 C. (with decomposition) (M. P. uncorrected) Z-thio 4,6 dicyclohexyl 5 methyl perhydrotriazine-- (1,3,5), M. P. 163-165 C.

The accelerating effect of this class of compounds is clearly apparent from a comparison of the mechanical values of unaccelerated mixtures and mixtures accelerated with, for example, 2-thio-5-methyl-perhydrotriazine- (1,3,5); The mechanical values were compared in mixtures with carbon black and mixtures with inactive carbon black.

The following examples further illustrate the invention,

but do not limit same:

Example 1 Mixtures with active carbon black:

Chloroprene polymer. 100.0 100. inc oxide 3.0 3. 0 Magnesium oxide. 4.0 4. 0 Active carbon blac 30. 0 30. 0 Phenyl-naphthylamin 2. 0 2. 0 Stearic acid 0. '0. 5 2-thio-5-methyl-perhydrotriazine- (1,3,5) 0. 5'

Tensile Elongation, strength, percent Loading atkgJcm. Min- Pressure utes 3007 5007 A B A B A B A B Tensile Loading atstrength, Elongation, MinkgJem. percent Pressure utes 300% 500% A B A B A B I A B Shore hardness Elasticity (percent Pres- Sc on sure Minutes A B A B Permanent set after- Min- Pressure utes 1 minute 1 hour A B A B 3.5 5 above 100. 29 above 100. 11 3.5 10 87 13 35 8 3.5. 15 46 9 6 3.5 20 22 9 6 3.5.. 40 15 6 4. 3.5 60 12 6 4 a 5 90 11 6 4 Deio BOO/13.0 330/123 Example 2 Mixtures with inactive carbon black:

Chloroprene polymer 100. 0 100.0 Zinc oxide 3.0 3. 0 Magnesium oxide 4. 0 4. 0 Inactive carbon black..-.. 30.0 30. 0 Phenyl-a-naphthylamine- 2. 0 2. 0' Stearic acid 0. 5 0. 5 2-thio-5-methyi-perhydrotriazine- (1,3,5) 0. 5

Tensile Loading atstrength, Elongation, Min! kgJem. percent Pressure utes- A B A B A B A B Share hardness Elasticity (percent Pres- Sehopper) sure Minutes A B A B T 2. In a' process'for'the' vulcanisation, with a member of the group consisting-"of zinc-oxide--andlead oxide, of a polymer of 2-chloro-butadiene-(1,3)- the step which comprises using a Z-thio-5-methyl-perhydrotriazine- (1,3,5) is used as a vulcanisation accelerator.

3.. In a process for the vulcauisation, with a member of the group consisting of zinc oxide and lead oxide, of a polymer of 2-chloro-butadiene-( 1,3), the step which comprises using a 2-thio-5-allyl-perhydrotriazine-(1,3,5) is used as a vulcanisation accelerator.

4. In a process for the vulcanisation, with a member of the group consisting of zinc oxide and lead oxide, ot a polymer -of '2-chloro-butadiene-(1,3), thestep which comprises usingv a. 2-thio-S-isopropyl-perhydrotriazine- (1,3,5) is used as a vulcanisation accelerator.

5.-In a-process-for-the vulcanisation, with a-member of the groupconsistinglof zinc oxide and lead oxide, of a polymer of 2 -chloro-butadiene-(1,35); the step which comprises using a t 2-thio-5-benzyl-perhydrotriazine- (1,3,5 )-is-used asa-vu1canisation accelerator.

6. In a process for the vulcanisation; with a member of the group consisting ofzinc oxide and lead oxide,-ofa polymer of l 2-chloro -butadiene-(1,3),; .the. .step vwhich comprises using; a Z-thid 4;6 dimethyl-perhydrotriazine- (1,3,5) isused as a vulcanisation acceleratorf References Cited in the, ifiler'of thispatent UNITED 'STATES- PATENTS 2,733,243 DAmicO.-.... Ian. 31, 1956 

1. IN A PROCESS FOR THE VULCANISATION WITH A MEMBER OF THE GROUP CONSISTING OF ZINC OXIDE AND LEAD OXIDE, OF A POLYMERR OF 2-CHLORO-BUTADIENE-( 1,3). THE STEP WHICH COMPRISES USING AS A VULCANISATION ACCELERATOR A COMPOUND OF TH EGROUP CONSISTING OF 1 